The present invention relates to hollow fiber tubular kidney dialyzers.
Kidney dialyzers function to remove toxic substances from the blood of patients suffering from renal failure. The dialyzers are fabricated with semipermeable membranes and dialysis is accomplished by flowing blood along one side of the membrane and a dialysate solution along the other side. During the dialyzing process, metabolites such as urea, uric acid, creatine, phosphorous and calcium in the blood diffuse from the blood to the dialysate solution through the membrane due to the lower concentration of metabolites in the dialysate solution.
Prior hollow fiber tubular kidney dialyzers comprised a bundle of several thousand individual microtubules, each consisting of a semipermeable material such as cellophane or Cuprophan.RTM.. The tubules were positioned in a cylindrical container and supported in a generally parallel orientation between two support members disposed at each end of the container. FIG. 4 illustrates this prior dialyzer tubule configuration. The blood was circulated through the tubules and the dialysate solution was circulated through the container around the outside of the tubules. To maximize the efficiency of the dialyzer, a great number of tubules were positioned within the container. Unfortunately, the high packing density and the randomly parallel orientation of tubules forced many tubules to mask, or come into contact with other tubules, precluding dialysis through the contiguous surfaces and thereby reducing the efficiency of the dialyzer. Furthermore, the tubules of the dialyzer expanded and contracted with changes in ambient temperature and humidity. The expansion of the tubules caused disruption of their original generally parallel orientation resulting in a more random and disordered positioning of the tubules. In this random orientation, there was even greater masking of the tubules which further reduced the efficiency of the dialyzer. Further, during operation of the dialyzer, the random orientation of the tubules caused the bunching of tubules with the accompanying formation of localized areas of low flow of dialysate solution within the dialyzer thereby even further reducing the efficiency of the dialyzer.
An object of the present invention is to provide an improved dialyzer and method of operation. Other objects and advantages of this invention will become apparent on a reading of the entire specification, including the drawings and claims.